Re: [PATCH] consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c

From: Kees Cook
Date: Wed May 22 2019 - 16:57:36 EST


On Wed, May 22, 2019 at 09:50:55AM +0800, Gen Zhang wrote:
> On Tue, May 21, 2019 at 01:44:33PM -0700, Kees Cook wrote:
> > This doesn't look safe to me: p->uni_pgdir[n] will still have a handle
> > to the freed memory, won't it?
> >
> Thanks for your reply, Kees!
> I think you are right. Maybe we should do this:
> kfree(p1);
> p->uni_pgdir[n] = NULL;
> Is this correct?

That's what I'm not sure about. I *think* so, from reading the code, but
I'd love to have Greg (or someone more familiar with the code) to
double-check this.

Otherwise, yeah, this looks right. Please send a v2 and we can debate
the correctness there, if it turns out to be wrong. :)

--
Kees Cook